基于ARCNET令牌总线的网络接口模块的设计

介绍了令牌总线网络——ARCNET的协议特点，重点阐述了一种基于ARCNET令牌总线的网络接口模块，详述了硬件结构设计及软件功能的实现。利用该模块搭建了ARCNET分布式温度监测网络，有很高的实时性和可靠性。     

控速令牌降低P2P网络维护开销

针对环形P2P网络中节点的维护消息数量随邻居节点数量线性增加和传统P2P网络令牌机制无法控制令牌数量的问题,提出了利用控速令牌维护环形P2P网络的方法.令牌以消息的形式在环形P2P网络中传递,令牌将途中经过的节点信息加入其中,其它节点利用令牌中的信息维持网络结构,并使用控速参数减少网络中的令牌数量.仿真结果表明,控速参数能够有效地降低P2P网络的令牌数量;随着网络规模的增大,节点平均维护开销维持不变.     

基于令牌传递的Hadoop双层环形网络优化研究

现有Hadoop环形监控网络宕机节点汇报率低，资源管理器与工作节点的沟通手段单一。针对上述问题，本文构建了一个基于令牌传递的双层环形网络模型，各个节点与前驱节点和后继节点建立双向链接，形成双层环形监控网络。之后，向工作节点发生令牌信号。当有动态调度策略需要实时数据或当节点的持有令牌时限到达时，该节点会汇报所有节点的状态信息，并将令牌传递给下一个节点。数据模拟实验证明该模型的故障汇报效率提升了20%，处理宕机节点的效率提升了59%。     

基于动态令牌托管的Ad hoc网络安全路由机制

作为Ad hoc网络大规模应用的先决条件,安全问题必须得到解决.为了加强节点间认证的安全性以及对合法路由的保护,提出一种基于动态令牌托管DTE(Dynamic Token Escrow)的Ad hoc网络安全路由机制,引入带有生存期的令牌控制网络实体间的信任关系,通过托管集实现本地化认证.仿真结果表明,在不安全的网络环境下,本文机制减少了认证消息交互,提高了路由建立的效率.     

Ad Hoc网络中基于信誉机制的介质访问控制协议

分析802.11协议存在的主要安全隐患,对协议进行必要的改进,提出基于信誉的多令牌介质访问控制协议,通过攻击检测和通信行为监测建立网络节点的信誉机制。以此为依据进行多令牌管理,规定只有持有令牌的节点才能访问信道,从而实现具有安全性保障的介质访问控制。利用NS进行仿真,结果表明该协议能够检测到网络中节点的恶意行为并迅速做出反应,较好地保证了网络性能。     

基于ARCNET网卡的机器人通讯模块的实现

ARCNET网络是一种基于令牌传递协议的网络，具有快速性、确定性、可扩展性和支持长距离传输等特点，非常适合工业实时控制。介绍了ARCNET网络及其特点，设计并实现了一种开放式的基于ARCNET网卡的机器人通讯模块。试验表明，该机器人通讯模块的设计能够满足基本控制要求，具有实时性好，可编程性高等优点。     

控制局域网ARCNET

ARCNET（Auxiliary Resource Computer Network）最初是在70年代末作为办公自动化网络发展起来的。后因其具有的快速、确定性性能和支持长距离的扩展非常适合于控制，而在工业自动化领域取得了成功。ARCNET被定义为ANSI/ATA 878.1。与办公自动化网络不同，①控制网络要求必须在时间可预测方式下传递信息，ARCNET的令牌传递协议提供了这种定时。ARCNET包长度在0～507字节内可变，开销很小。与ARCNET高速率结合（通常为2.5Mbps）可以实现对短信息的快速反应。ARCNET具有内置的CRC-16错误检测并支持包括光纤在内的许多物…     

短波地空IP网络的MAC协议设计与仿真

合适的多址接入MAC(multiple access)协议是提升网络性能的关键。根据短波地空IP网络通信覆盖范围广、难同步,空中节点信息可能丢失的特点,设计出该网络一种新型的带预约短波令牌协议HFTP-R(High Frequency token protocol with reserve)。该协议在初始化时由空中节点随机加入地面节点形成的簇,并通过预约信道向地面节点发送预约信息,从而获取令牌接入信道,地空之间不需要保持逻辑环的"封闭性"。最后,利用OPNET软件构建了HFTP-R的仿真框架,与其他MAC协议作了仿真比较。仿真结果表明,HFTP-R减少了短波令牌协议HFTP(High Frequency token protocol)的令牌丢失次数和传递开销,能提供较好的实时性、较高的网络吞吐量和业务传输成功率,在特定需求下较其他MAC协议更有优势,可满足网络需要。     

基于令牌的ARCNET故障侦听与解码原理及实现

基于令牌传输协议ANSI/ATA878．1及ARCNET网络数据报文的编码原则，提出了直接截获传输介质信号流，解码复现信息帧的解码原理及其在实际工程项目中的具体实现。     

面向单目标跟踪的临时簇构建算法研究

在目标跟踪中引入分簇机制使得跟踪计算任务可以以簇为单位进行,也可以在持久跟踪中将任务在簇间进行切换;文章针对无线传感器网络单目标跟踪提出一种临时簇构建算法(TCA),算法从感知到目标出现的节点中选出合适的节点,组建起临时簇进行目标跟踪运算,算法采用令牌传递方式来防止多个簇同时跟踪一个目标,使绝大多数节点均处于休眠状态;仿真实验结果表明,TCA组簇快速且能有效地控制整个网络的能耗。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.